The invading army led by Dark God Vecta, Gabriel Miller, numbered 50,000, while the garrison led by Integrity Knight Bercouli only had 5,000. The Integrity Knights, led by the "Sky-piercing Sword" Fanatio, kept fighting, trying to reverse this numerical disadvantage. However, the enemy's mountain goblins used cunning tactics to penetrate the defense line and launch an attack on the supply troops in the rear. In order to protect Kirito who is in a state of confusion, young trainees Ronye and Tize are in crisis. Moreover, the cunning Dark Magician Guild leader Ti. Ai Elu, who is known as the invading army, is also planning to launch a terrifying large-scale magic to annihilate the garrison in one fell swoop... At this moment, where will Asuna, who has logged into the Underworld, go?